738
FXUS65 KBYZ 251202
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
602 AM MDT THU JUN 25 2026
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS LIKELY TODAY; A FEW STRONG
THUNDERSTORMS POSSIBLE, ESPECIALLY EAST OF BILLINGS.
- STRONGER WEATHER SYSTEM EXPECTED FRIDAY THROUGH THE WEEKEND,
BRINGING FREQUENT SHOWERS AND EMBEDDED THUNDERSTORMS (SEVERE
STORMS POSSIBLE FRIDAY & SATURDAY), COOLER TEMPERATURES AND
BRISK WINDS. HIGH ELEVATION SNOW IS POSSIBLE SUNDAY INTO MONDAY.
- EXACT TRACK OF THE LATE WEEK SYSTEM REMAINS UNCERTAIN, AND WILL
AFFECT PRECIP AMOUNTS AND COVERAGE.
- WARMING AND DRYING TREND NEXT TUESDAY & WEDNESDAY.
UPDATE
SHOWERS AND ISOLATED THUNDERSTORMS ARE TRACKING ACROSS THE
SOUTHERN MOUNTAINS AND FOOTHILLS THIS MORNING, AS MOISTURE AND
ENERGY STREAM INTO THE AREA AHEAD OF AN APPROACHING SHORTWAVE.
SOME LOCATIONS IN AND AROUND THE MOUNTAINS HAVE PICKED UP CLOSE TO
A TENTH OF AN INCH OF PRECIP OVERNIGHT. EXPECT SHOWERS AND
THUNDERSTORMS TO INCREASE IN THIS MORNING, SPREADING WEST TO EAST
ACROSS THE AREA THIS AFTERNOON INTO THE EVENING. HAVE UPDATED
POPS AND THUNDER CHANCES THIS MORNING TO CURRENT TRENDS.
OTHERWISE, THE GOING FORECAST COVERS OUR THUNDERSTORM THREAT FOR
THIS AFTERNOON AND EVENING WELL. AN UPDATED AVIATION DISCUSSION IS
BELOW. STP
DISCUSSION
THROUGH NEXT WEDNESDAY...
FLAT RIDGING EXISTS OVER THE REGION AHEAD OF A SHORTWAVE MOVING
THRU THE PACNW EARLY THIS MORNING. PWATS ARE STEADILY INCREASING,
COURTESY OF A PERIOD OF HIGH PLAINS MOISTURE RETURN, AND WILL
REACH NEAR AN INCH TODAY. LARGE SCALE ASCENT INCREASES FROM THE
WEST BY 12Z, WHICH COMBINED WITH THE MOISTURE AND EASTERLY
SURFACE WINDS SHOULD RESULT IN SOME SHOWER ACTIVITY DURING THE
MORNING. THE AMOUNT OF SHOWERS AND CLOUD COVER IN THE MORNING WILL
PLAY A LARGE ROLE IN DETERMINING OUR SEVERE RISK BY THE AFTERNOON
AND EVENING. HIGH RES MODEL CONSENSUS SHOWS AXIS OF HIGHEST
INSTABILITY (700-1000 J/KG) WITH NEAR 30KTS OF BULK SHEAR IN AN
AREA INCLUDING BIG HORN, SHERIDAN, SOUTHERN ROSEBUD AND POWDER
RIVER COUNTIES...AND IT IS HERE WHERE THERE IS THE GREATEST RISK
FOR STRONG TO POTENTIALLY SEVERE STORMS. HAIL, WIND AND HEAVY
RAIN ARE POSSIBLE WITH ANY STRONGER STORMS, BUT AGAIN WILL NEED TO
MONITOR MESOANALYSIS CLOSELY AS WE PROGRESS THROUGH THE DAY. IF
SURFACE HEATING RESULTS IN ENOUGH DESTABILIZATION BEFORE THE TROF
AXIS PASSES THE RISK OF STRONGER STORMS COULD SHIFT A BIT
WESTWARD, BUT THE MORE PROBABLE SCENARIO IS THE WEST WILL HAVE ITS
AIR MASS MUDDLED BY SHOWERS AND CLOUD COVER. ONSET OF
SOUTHEASTERLY LOW LEVEL JET WILL ENHANCE PRECIP CHANCES IN OUR
EAST BY EVENING, EVEN AS THE RISK OF STRONGER STORMS BEGINS TO
LESSEN.
FLOW ALOFT BACKS TO THE SW FRIDAY ALLOWING FOR A WARMER DAY AND
LATER DEVELOPING CONVECTION WITH LATE DAY HEIGHT FALLS. AFTER
TEMPS IN THE 70S TODAY WE SHOULD SEE UPPER 70S TO LOWER 80S
TOMORROW. SPC HAS HIGHLIGHTED OUR EAST WITH A MARGINAL RISK OF
SEVERE T-STORMS, BUT WITH STEEPER LOW LEVEL LAPSE RATES AND
SIMILAR MOISTURE/INSTABILITY THERE MAY BE A HIGHER RISK OF STRONG
WINDS WITH CONVECTION THAT DEVELOPS IN THE WEST BY LATE AFTERNOON.
OVERALL, RISKS WILL AGAIN INCLUDE HAIL, WIND AND HEAVY RAIN
(PWATS STILL AROUND AN INCH).
DEEP LOW WITH A SIGNIFICANT LOW HEIGHT ANOMALY WILL TRACK THRU THE
NORTHERN ROCKIES OVER THE WEEKEND AND INTO MONDAY. THE LOW
TRACKING TO OUR WEST AND NORTH WILL PREVENT ANY PERIODS OF
ENHANCED UPSLOPE PRECIP, BUT THERE WILL BE SEVERAL EMBEDDED
SHORTWAVES WHICH WILL PROVIDE FREQUENT SHOWERS AND T-STORMS.
SHOWERS AND T-STORMS ARE LIKELY SATURDAY, WITH A CONTINUED RISK OF
SEVERE STORMS. THE RISK OF DRY-SLOTTING BY SUNDAY WILL NEED TO BE
WATCHED BUT RECENT MODEL TRENDS SHOW A STRONG ENOUGH TRAILING WAVE
TO BRING MORE SHOWERS AND WEAKER T-STORMS BY AFTERNOON AND
EVENING. IT IS ALSO POSSIBLE THAT PRECIP ASSOCIATED WITH A TROWAL
IS ABLE TO WRAP INTO OUR W/NW BY MONDAY, BUT THIS IS WHERE MODEL
SPREAD INCREASES EVEN MORE. ON THE BACK SIDE OF THE LOW WE SHOULD
SEE BRISK WINDS DEVELOP BY MONDAY WITH HIGHEST GUSTS (PERHAPS
40-50 MPH) ALONG WESTERN FOOTHILLS. FINALLY, IT IS THE LATTER PART
OF THE WEEKEND WHEN HIGH ELEVATION SNOW IS A STRONG POSSIBILITY
OVER WESTERN MOUNTAINS, WITH SNOW LEVELS AS LOW AS 8.5-9.0KFT MSL.
A LOT OF DETAILS TO BE WORKED OUT, BUT CONFIDENCE IS HIGH FOR
VARIOUS IMPACTS FROM THE DEEP UPPER LOW FROM LATE FRIDAY INTO
MONDAY. HEADS UP IF YOU HAVE OUTDOOR PLANS.
THE PROBABILITY FOR AN INCH OF PRECIP OVER THE WEEKEND IS 10-30%
ACROSS THE LOWER ELEVATIONS, AND UP TO 40-50% OVER WESTERN
MOUNTAINS.
THE LOW FILLS AND LIFTS NORTH OF OUR REGION BY MONDAY/MONDAY
NIGHT, AND TROWAL OR NOT, WE SHOULD SEE DRYING WITH THE DEVELOPING
WEST WINDS. THERE IS STRONG ENSEMBLE CONSENSUS FOR A WARMING AND
DRYING TREND TUESDAY & WEDNESDAY, AFTER A SEASONABLY COOL
SATURDAY-MONDAY.
JKL
AVIATION
SHOWERS AND THUNDERSTORMS WILL INCREASE OVER THE WEST THIS
MORNING, SPREADING EAST THIS AFTERNOON INTO THE EVENING AS A
DISTURBANCE MOVES THROUGH THE REGION. THUNDERSTORMS COULD BE
STRONG, WITH HEAVY RAIN, HAIL AND GUSTY WINDS. LOCALIZED MVFR TO
IFR CONDITIONS ARE POSSIBLE UNDER THE STRONGER SHOWER/THUNDERSTORM
ACTIVITY. WIDESPREAD VFR CONDITIONS WILL RETURN THIS EVENING INTO
TONIGHT.
MOST LIKELY THUNDERSTORM TIMING:
KLVM 18Z-00Z
KBIL 19Z-01Z
KSHR 20Z-01Z
KMLS 22Z-03Z
STP
PRELIMINARY POINT TEMP/POPS
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 073 055/084 058/076 052/070 049/072 051/079 053/083
7/T 32/T 79/T 85/T 33/T 11/B 11/U
LVM 075 049/079 048/068 041/062 040/064 042/073 044/079
9/T 45/T 6+/T 96/T 55/T 22/T 22/T
HDN 076 052/086 056/077 050/072 047/074 048/080 050/084
8/T 32/T 78/T 85/T 32/W 21/U 10/U
MLS 075 053/083 059/078 053/073 050/073 051/078 054/083
6/T 51/B 76/T 74/T 32/T 21/U 11/U
4BQ 072 053/085 060/079 054/074 051/074 051/079 054/084
8/T 72/T 55/T 83/W 42/T 11/U 11/U
BHK 074 050/081 057/081 052/074 049/073 048/077 051/083
2/T 70/B 65/T 83/W 43/T 21/U 11/U
SHR 074 049/083 053/075 047/070 043/073 045/078 047/083
8/T 42/T 57/T 74/T 31/B 11/U 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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